Background | Conditions | Policy Options | Specific ASCE recommendations | Sources

Dams provide tremendous benefits, including water supply for drinking, irrigation and industrial uses; flood control; hydroelectric power; recreation; and navigation. However, dams also represent one of the greatest risks to public safety, local and regional economies and the environment. Historically, some of the largest disasters in the United States have resulted from dam failures. In 1889, 2,209 lives were lost when the South Fork Dam failed above Johnstown, Pennsylvania. The 1928 St. Francis Dam failure killed 450. During the 1970s, the failures of the Buffalo Creek Dam in West Virginia, Teton Dam in Idaho and the Toccoa Falls Dam in Georgia collectively cost 175 lives and more than $1 billion in losses. Such dam failures as Silver Lake Dam in Michigan in 2003 ($100 million in damages and economic losses of $1 million per day) and the Big Bay Lake Dam in Mississippi in March 2004 (100 homes destroyed) are current reminders of the potential consequences of unsafe dams.

In order to provide safe, continuing service, dams require ongoing maintenance, monitoring, frequent safety inspections and rehabilitation. Aging dams often require major rehabilitation to assure their safety. Downstream development below dams is increasing dramatically, and continuing scientific research of dam failure mechanisms, such as earthquakes and major flood events, frequently demand repairs to dams constructed long before these advances were realized. Many state dam safety programs do not have sufficient funding or qualified staff to effectively regulate dams under their authority. State programs regulate 95% of the 79,000 dams in the United States, while the federal agencies own or regulate only 5% of the nation's dams.

Like all man-made structures, dams deteriorate. Deferred maintenance accelerates deterioration and causes dams to be more susceptible to failure. As with other critical infrastructure, a significant investment is essential to maintain the benefits and assure the safety that society demands.

In the past two years, more than 67 dam incidents, including 29 dam failures, were reported to the National Performance of Dams program, which collects and archives information on dam performance as reported by state and federal regulatory agencies and dam owners. Dam incidents are such events as large floods, earthquakes or inspections that alert dam safety engineers to deficiencies that threaten the safety of a dam. Due to limited state staff, many incidents are not reported; therefore, the actual number of incidents is likely to be much greater.

The number of high-hazard potential dams (dams whose failure would cause loss of human life) is increasing dramatically. Since 1998, the number of high-hazard-potential dams has increased from 9,281 to 10,213, with 1,046 in North Carolina alone. As downstream land development increases, so will the number of high-hazard potential dams. As these dams often require major repair to accommodate more stringent inspection, maintenance and design standards, financial support for state dam safety programs must keep pace.

Even more alarming, states presently report more than 3,500 "unsafe" dams, which have deficiencies that leave them more susceptible to failure. Many states have large numbers of unsafe dams, including Pennsylvania (725), New Jersey (583), and New Hampshire (357). Many state agencies do not report statistics on unsafe dams; therefore the actual number is potentially much higher.

The combined effect of rapid downstream development, aging/non-compliant structures and inadequate past design practices, coupled with a predicted increase in extreme events, demands fully funded and staffed state dam safety programs, as well as substantial and proactive funding for dam repairs.

Some progress is being made through the repair of small watershed dams constructed with assistance from the United States Department of Agriculture (USDA), beginning in 1948. This is only a small portion of the total number of non-federal dams. On the federal side, federally owned and federally regulated hydropower dams are in good condition; however, continuing budget restrictions and increased attention to security are placing pressure on and limiting many agency dam safety programs.

While the recent passage of the National Dam Safety and Security Act of 2002 (Public Law No: 107-310), which provides funding through grants, has improved state dam safety programs, it does not provide funding for needed repairs. It is estimated that $10.1 billion is needed over the next 12 years to address all critical non-federal dams--dams that pose a direct risk to human life should they fail. In the meantime, the 79,000 dams in the U.S. National Inventory of Dams continue to age and deteriorate, yet there is no national funding program to fund the repair of unsafe dams.

Since the last ASCE Report Card, the National Dam Safety Act of 1996 was reauthorized in 2002, increasing the authorization to $8.0 million. To date, however, funding has remained at pre-reauthorization levels of $5.5 million. Under this program, state dam safety agencies have received grants totaling nearly $22 million to assist with improving dam safety regulatory programs by procuring equipment, implementing new technology, and enabling more-frequent inspections. The program also provided opportunities for continuing education to dam safety engineers, and funding for research to advance the technology of investigations, construction, and rehabilitation of dams, but no funding to repair unsafe dams.

According to results of a study by the Association of State Dam Safety Officials, the total investment to bring U.S. dams into safety compliance or to remove obsolete dams tops $30 billion. Except for a handful of state programs offering low-interest loans to dam owners, there are no funding sources for dam rehabilitation or repair. Private owners have the greatest need for funding. The Small Watershed Rehabilitation Act addresses less than 10% of the nation's dams--the remaining 90% demand similar attention.

Representative Sue Kelly introduced HR 5190, the Dam Repair and Rehabilitation Act, in the 108^th Congress. The bill would provide $350 million over 4 years for the repair, rehabilitation or removal of non-federal, high-hazard, publicly owned dams. The bill will be re-introduced early in the 109^th Congress.

Four years ago, few state dam safety programs were adequately funded or staffed. Today, that situation remains the same. On average nationwide, there are 268 state-regulated dams per full-time equivalent (FTE) staff. In 13 states, this number exceeds 500, and four report more than 1200 dams per FTE staff. In 1998, a Texas House Committee recommended adding 15 staff members to that state's six-member dam safety team; today, there are still only six staff members responsible for inspecting nearly 7500 dams. One Texas official commented that, "because of inadequate staffing, some dams would not be examined for three centuries."

Since the last Report Card, Delaware has created a dam safety program, leaving Alabama as the last remaining state that has not passed dam safety legislation. As a result, an estimated 2,100 dam structures--perhaps more--are unregulated. At last count, 171 of these structures were classified as high-hazard.